adding comments within reference brackets

I was wondering if anyone knew how to insert comments like (see REFID100) (cf. REF100) (for example see REF100; REF101; REF102) etc. inside cited references in a document. Whenever I add these comments to the reference codes and the bibliography is updated the original text is lost. I would like to have the flexible to update and have this information added at the same time. 

Any help would be much appreciated.